The present invention relates to a three-dimensional displacement measurement apparatus and method, and more particularly, to a three-dimensional displacement measurement apparatus and method that measures fine displacements in three dimensions of a specific point of a precision mechanism.
Products that require precise mechanisms require efforts for quality stability from the stage of design through to manufacture, and use structural analysis methods that are incorporated from the design stage as CAE. However, when there are fine displacements of mechanism systems under compounded conditions of the influence of heat and the like to coupling portions of assembly parts, the analysis is difficult and as a result, there is a large influence to both the quality of the final product and the manufacturing yield. Because of this, there is a sharply increased necessity for high-precision three-dimensional displacement measurement apparatus so as to enable product design incorporating consideration for fine displacements that occur due to changes in the installation environment (such as temperature and humidity and the like).
Conventional three-dimensional measurement apparatus include contact-type measurement apparatus that measure by using a probe to a surface for measurement, and three-dimensional measurement apparatus of the non-contact type which use a camera to measure a displacement in the xy-directions, and an interferometer to measure a displacement in a Z-direction. In addition, there is also the triangular measurement quantity type and the static capacitance type of non-contact displacement measurement apparatus for the Z-direction.
The photointerference type is the most suited for displacement measurement in the assembly stages of products.
However, each of the types of three-dimensional measurement apparatus mentioned above cannot measure the true three-dimensional displacement measurement of a measurement point on an object plane. This is because the measurement point is not tracked in the Z-direction in accordance with displacements in the xy-directions.
For determining a true displacement due to heat measurement of the three-dimensional displacement while tracking the measurement point with respect to an initial value is essential.